If the example is Postmarked
and it is prior to 1924 then it must be a De La Rue J1a.

The J1a has a W.7 Watermark and
a Horizontal Mesh.
The gum on a UHM example is brown in colour.

Colour ranges from Carmine to
dull carmine to carmine-pink to dull pink to Ruby.
(Carmine-pink and Ruby are found mainly in Booklets.)

The De La Rue Company supplied
paper fort he Penny Dominion from 1908 to 1924.
The paper is recorded as "De La Rue", but there were in fact several
different papers.
Roughways Paper Mills supplied the paper from 1908 to 1913. Then
William Howard & Sons
provided the paper. Different dandy rolls were used, which can be
identified by the different
position and size of the watermark letters in the selvedges. The Roughways
paper had
watermark letters 14mm high, while the Howard paper watermark letters were
11.5mm high.
All papers were watermarked with multiple NZ & Star and had brownish gum.